A correlation between gas evolution in electrically stressed oils and other estimates of oil aromatic content

Ability to absorb hydrogen under electrical stress has long been considered an important property of cable oils, and various laboratory test techniques to measure this property have been developed (4,6,8,17,19,20). However, all these direct measurements of the tendency of an oil to evolve or absorb gas require complicated apparatus with high voltages. Such apparatus is suitable for referee and research purposes, but a simpler method for predicting gassing tendencies would be valuable for control and screening purposes. The gassing tendency has been generally related to the aromatic content of the oil. For example, specific optical dispersion has been related to gas absorption (24), is now being used in oil continuity tests, and an ASTM standard is being prepared. However, specific optical dispersion is increased not only by aromatic content but by the extent to which aromatic bonds are conjugated. For example: equation It seems unlikely that such conjugation would affect hydrogen absorption to the same extent.